The invention relates generally to engines of the type which are powered by pressurized gases and which convert gas pressure into mechanical energy.
In developing new sources of energy for replacing increasingly scarce and expensive fossil fuels, greater attention is being directed to the harnessing of naturally occurring pressurized gases from geothermal sources. Geothermal gases occur in great abundance in certain locations throughout the world and such gases contain potentially valuable energy which is usually wasted. One problem in harnassing geothermal gases is their generally caustic nature which causes destruction of metal parts such as cylinders and pistons. Geothermal gases also tend to have an unpleasant odor and may even be toxic, which makes any leakage from devices or systems which employ such gases highly undesirable. It is therefore necessary, when seeking a means for harnassing geothermal gases, to eliminate to the extent possible all potential leaks and any possible contact between the gases and metal parts. Because geothermal gases are potentially volatile, it is also important to avoid sources of sparks and to minimize friction in any machine which harnasses geothermal gases. The harnassing of naturally occurring pressurized gases can become an important energy resource for the future, offering a steady source of energy far more reliable than alternative energy sources such as solar or wind power.